MODIFICATION OF INDONESIAN PEAT SOIL USING HYDROGEN PEROXIDE AND MODELLING OF ITS ADSORPTION TOWARDS POTASSIUM ION (K+) IN AQUEOUS SOLUTION Galuh Yuliani(1*),Suci Karina(1), Mita Nurhayati(1), Siska Mutiara(1), Mamun Mollah(2) and Shangeetha Ganesan(3)
1. Chemistry Department, Universitas Pendidikan Indonesia, Jalan Dr. Setiabudi 229 Bandung 40154, West Java, Indonesia
2. School of Chemistry, Monash University, Clayton 3800, Australia
3. School of Chemical Sciences, Universiti Sains Malaysia, 11800 USM, Penang, Malaysia
Abstract
Peat soil is formed from plant vegetation that was buried for centuries. Peat contains many functional groups -COOH and -OH and this lead to its potential application as an adsorbent for metal ions and organic compounds. However, the adsorption capacity of natural peat was reported to be lower than other adsorbents. Therefore, this study aims to modify the peat surface using H2O2 and to apply the modified peat as an adsorbent for K+ ion in aqueous solution. The residual concentration of K+ ion was determined using Atomic Absorption Spectrophotometer (AAS). Peat modification was carried out using hydrogen peroxide 10% solution for 30 mins. The FTIR spectra indicated an increase in the intensity of of hydroxyl groups (-OH) at 3400 cm-1 and carboxylic groups (-COOH) at 1700-1720 cm-1. The SEM photos indicated increase in porosity of the modified peat. From the BET analysis, it was found that the surface area of peat increased from 56.221 m2/g to 81.346 m2/g upon modification. From the adsorption test, the adsorption capacities of modified peat and raw peat were 37.40 mg/g and 59.53 mg/g, respectively. Furthermore, the adsorption data were fitted using adsorption isotherm models and it was found that the data plots follow the Freundlich isotherm model. To confirm the adsorption data analysis, a computational study was conducted using Density Functional Theory (DFT). From DFT calculation, the interaction energy of peat and K+ ion was lower after peat modification, indicating that K+ ion strongly adsorbed into modified peat.
